The Joe Gibbs Racing team also will lose 75 points in the owner standings and the team’s car chief, Wesley Sherrill, also was suspended for six races. Both Grubb and Sherrill are on NASCAR probation for six months.

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Joe Gibbs Racing will appeal the penalty but will not ask for the suspensions to be deferred until the appeal is heard because, currently, the suspensions go through the remainder of the regular season. If Grubb remained atop the pit box and the suspension was upheld, he would miss the start of the Chase for the Sprint Cup. The team did not immediately announce a replacement for Grubb for the race this weekend at Pocono.

The penalty drops Hamlin from 11th to 21st in the standings, but with a win earlier this year at Talladega, he is in good shape to make the Chase. His only problem could be if he runs poorly the next six weeks and if a winless driver wins each of the final six regular-season races.

The penalty was considered a P5 on NASCAR’s new scale that rates penalties from P1 (lowest) to P6 (highest). Because it was found postrace, the points penalty was increased by 25 points and the fine was increased by $50,000 than they would have been if found prior to postrace technical inspection.

The block-off plates are intended to seal the driver’s compartment to keep hot fluids, smoke and fire from getting to the driver. Air flow through the block-off plates could help with the car’s aerodynamics during an event, and it is an obvious safety issue. According to the NASCAR rule book, a P5 penalty is serious enough that intent does not matter.

"P5 penalties, in general, are extremely serious," the rule book states. "They represent other key safety areas not mentioned elsewhere in this (penalty) section and potentially performance-related areas of the car that might or might not afford a competition advantage, but with a violation occurring in such a fashion that it would be naive to attribute the violation to an accident, omission, or misunderstanding, even if it was an accident, omission, or misunderstanding."

NASCAR determined that the team violated rules that prohibit air from flowing from one area of the interior of the car to another area or outside of the car as well as not having the interior sheet metal properly sealed and caulked.